Preventing E-Mail Security Abuses
Packet-filtering messages from sources that are known to flood is effective but reactionary because the mail buffers and disk space can be monitored for excessive use. Spoofing and nonrepudiation are effectively combated with digital signatures.
Digital signatures are easily implemented from Outlook Express 5.0 via the Tools, Options selection under the Security tab, in which encryption and digitally signing can be configured for outgoing messages. The user and recipient must share a common certificate authority.
Virus attacks are difficult to filter out, especially when e-mail encryption is involved. Several virus scanners are available, but are of limited effectiveness. If the scanner has an error and starts dropping all e-mail messages, regardless of viral content, the network and company can end up in a worse predicament than dealing with the virus. Denial of service is a serious downside to these tools, which means that careful monitoring and reaction time are key to successful implementation.